Fig. 5

The influence of overproduction of periplasmic chaperones on difficult-to secrete HbpD constructs. A Schematic representation of pTUM plasmids used in this study indicating the different combinations of chaperones (FkpA, SurA and Skp) and folding catalysts (DsbA and DsbC) used. The plasmids are pACYC derivatives, which was used as negative control. B–D Coomassie-stained SDS-PAGE gels showing expression of DTS HbpD constructs in combination with the pTUM plasmids. Tested were HbpD-ELL (B), HbpD-SpT2-Calm (C) and HbpD-GFPnb (D). E–G Fold change of surface displayed HbpD constructs when co-expressed with periplasmic chaperones, as shown by flow cytometry using anti-ESAT6 (E), coupling of SpC2-mScarlet to SpT2 (F) and binding of GFP to the HbpD-GFPnb (G). **p < 0.01; ***p < 0.005; ****p < 0.001